ZZ plants are very popular for their hardy nature and waxy look, making them look like artificial plants. However, not every plant owner can keep them thriving.
Some enthusiasts struggle to keep their ZZ plant alive. One common issue that most beginners go through is the yellowing of leaves. But what causes yellow leaves in the ZZ plant, and how can we fix it? Let’s find out!
Overwatering is the primary cause of yellow leaves in the ZZ plant. Apart from that, inadequate lighting, lack of nutrients, root rot, and a pest infestation can also lead to yellow leaves in the ZZ plant. Move the ZZ plant to a brightly lit spot and water only when the top 2-3 inches of soil is dry.
Yellowing of leaves can happen due to multiple reasons. What’s important is identifying the causes of yellow leaves and taking appropriate action to fix the issue.
With that out of the way, let’s dive into the causes of yellow leaves on the ZZ plant and how we can fix the same.
Table Of Contents
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What causes yellow leaves on my ZZ plant?
There can be multiple causes of yellow leaves on the ZZ plant. However, you must begin by checking the watering and lighting schedule. After that, you can move on to humidity, temperature, pests, and so on.
In most cases, overwatering is the reason behind the yellowing of ZZ plant leaves.
ZZ plants directly react to overwatering by yellowing the leaves. ZZ plants are slow-growing plants; hence people think of it as an underwatering problem and end up overwatering it.
When the ZZ plant’s roots get exposed to a wet environment for a certain period, it introduces fungal growth and root rot.
A plant going through root rot ends up suffering water deficiency, and the roots are unable to send the essential nutrients from the soil to the plant. The adverse effect can be seen as the leaves of the ZZ plant starts turning yellow.
Also read: Overwatering vs. Underwatering
Low humidity level
As winter begins, the air in our home becomes dry. And if you are using a heat source like a furnace to heat your home, the humidity level goes down even further.
As the humidity level starts dropping, the ZZ plants react to lack of humidity by curling and yellow leaves.
Also read: How much humidity do ZZ plant need?
Low lighting is one of the most common causes of yellow leaves in the ZZ plant. Yes, the ZZ plant is often sold as a low lighting plant, but that doesn’t mean the plant can survive the bare minimum.
ZZ plant often needs decent low-medium lighting to survive and grow. If enough lighting is not provided, then the plant is likely going to suffer.
The photosynthesis process of the ZZ plant is often slowed down as it doesn’t get enough lighting. That results in the lower leaves of the ZZ plant turning yellow.
Also read: How much light do ZZ plant needs?
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ZZ plants can’t tolerate high-temperature conditions, but you may often hear some people saying, “ZZ plants can thrive in dry conditions” as a counter-argument.
It’s sad to see how they relate dry conditions directly with high temperatures.
Yes, that’s right, that high temperature can also cause dryness, but that’s the case when plants aren’t getting enough water and frequent mist.
Plant owners mostly find it unnecessary to repot the plant, which results in a root-bound situation. A ZZ plant needs to be repotted once every 12-18 months, usually depending upon the plant’s size and growing speed.
To know if your plant is asking for a new pot, here are a few signs
- Roots seem to be coming out of the drainage holes of the pot.
- The plant feels heavier than usual.
- Leaves start getting yellow.
- In some cases, the plant starts wilting and drooping.
Here’s a list of a few significant consequences if not repotted the ZZ plant for too long
- A root-bound plant tends to become weak and can suffer fungal disease.
- The plant becomes stressed, which slows down the growing speed.
- The plant becomes heavy and can lean over.
- The plant starts to wilt.
Repotting a ZZ plant during the dormant season could be a bad idea as the plant might get stressed out due to repotting.
Also read: Do ZZ plant like to be root bounded?
One of the causes of yellow or black spots on the ZZ plant is pests attack.
The most common pests eagerly waiting to attack your ZZ are Aphids, whiteflies, spider mites, etc.
Most of the pests species are very tiny in size and hence can’t be seen through naked eyes, so they can harm the plant a lot if they remain unnoticed for a long duration.
If you try to speed up the ZZ plant’s growth with excessive fertilizer feeding, then the roots will start suffering, and later the leaves turn yellow. As a result, the plant starts wilting.
Most new plant owners often mistake overfertilizing their ZZ plant, which results in poor growth and wilting of the plant.
However, under fertilization is equally bad for your ZZ plant. If you do not provide enough nutrients to the plant, then the growth is likely to suffer, and yellow leaves are a common sign of slow growth and wilting.
Also read: Do ZZ plant need fertilizer? How much?
What do I do if my ZZ plant has yellow leaves?
To fix the problem of yellow leaves in the ZZ plant, we need to take care of the watering schedule, lighting, and fertilization of the plant.
However, a key point to note here is if the leaves have already turned yellow, you need to clip that part off. It is impossible to turn the yellow leaves green again.
Nevertheless, we can prevent new leaves from turning yellow by fixing some things discussed below.
When watering the ZZ, do it thoroughly until the water drips down from the pot’s drainage holes.
Don’t water it again till the top two inches of the soil get completely dry.
Remember that less water is better than excessive water in ZZ plants because overwatering is much more problematic than underwatering the plant.
Do not water the plant unless needed, as it will not boost the growing speed of the ZZ but will cause several issues.
If you are a new plant enthusiast, you can purchase a moisture meter that will help you determine the plant’s water requirements.
And remember, the overwatering problem is especially relevant in winter when the plant reduces water consumption. It would be best if you considered reducing watering the plant during winters.
Also read: How often should I water my ZZ plant?
“The higher the humidity, the better the plants do.”
The ZZ thrives in a reasonably humid climate. It prefers the humidity to be around 40-50%. To measure the humidity, you can purchase a hygrometer if you are willing to invest.
ZZ plants can tolerate the dry surroundings, but you should prefer maintaining a balance and keep an eye on the plant and try to provide at least a little bit of humidity.
How to keep the humidity up in your home?
- The easiest way to keep the humidity maintained for the plant is misting.
- Fill a spray bottle with some water and spray it all over the plant and wipe it with a cotton ball or tissue paper.
- Mist the plant at least once every three days and prefer using purified or distilled water mixed with some neem oil.
- Leave some small jars, glass vessels, or bowls filled with water scattered around your plant.
- Keep the jar/glass open so that the water could evaporate. It would work better if you use warm water.
- If you can collect some seashells, go and get some. Scatter them all around the soil surface of the pot.
- Seashells collect the water from around and will evaporate and will contribute to increasing humidity.
- Hang dry your clothes in the same room where you keep your ZZ plant. This method alone can increase the humidity up to 10%.
- After taking a shower, keep the bathroom door open so that the steam could come out and increase the relative humidity by a little bit.
- If you can invest a bit more, go for a good room humidifier.
The majority of the house plants are sensitive to direct sunlight exposure, and ZZ plants are not any different. Never place your ZZ plant under direct sunlight, as it can burn the leaves of your plant.
This plant does love bright indirect light; if you keep it in harsh direct sunlight, the leaf starts yellowing, so keep it in a place where it receives at least a little bit of sunlight, and it will thrive.
However, if the plant is kept under extremely low lighting conditions, the plant is likely to suffer.
Low lighting can hinder the photosynthesis process leading to poor growth and yellowing of leaves.
Ideally, place your ZZ plant in a spot where it gets enough indirect lighting.
ZZ plants prefer a warm tropical climate. Thus the ideal temperatures should be between 18-25° C.
An ideal way to maintain the temperature is by keeping your home’s thermostat in the ideal range.
However, make sure the plant is placed away from vents, as drafts of winds can also result in the yellowing of the leaves.
If you have been keeping the ZZ plant on your patio, it would be ideal to bring them inside as the mercury level starts dropping.
Repotting gives more space for the plant to grow its roots comfortably and provides the plant a fresh new soil with ample nutrients.
However, there are two essential factors to keep in mind while repotting a ZZ plant. These include new pot and fresh soil.
A rule of thumb is you must always choose a pot that is one size bigger than the current one. For example, if your ZZ plant is potted in a 6-inch pot, you must be moving the plant to an 8-inch pot.
Apart from that, the choice of potting soil is critical as well. Most of the commercial potting mix will work well with the ZZ plant.
The potting mix available in the market has a blend of perlite, peat moss, and even sand (sometimes) to ensure proper drainage for the plant.
However, If you wish to make your soil mix for your ZZ plant, mix regular potting soil with the cactus mix to ensure proper drainage and quick nutrition absorption.
There are several methods to get rid of pests. Here are the most effective methods that will surely help keep your plant free from irritating pests.
As I like to go organic, one of the natural and simplest methods I often recommend to everyone to get rid of the pests is using neem oil.
The process is straightforward: Dip a cotton ball or tissue ball in a diluted neem oil solution and apply it on a single ZZ leaf and leave it for a whole day to make sure your plant won’t go through any problem.
If your ZZ doesn’t develop any problems, then apply it all over the plant. Using it once a week will be enough.
You can also mist the diluted solution for quicker application.
Many people ask me about its side effects. As far as my experience goes, I have not seen a single side effect of using neem oil on most of my houseplants.
As it is non-toxic, no safety precautions need to be taken while using it until and without being allergic to it.
Neem oil works exceptionally well to fight against white powdery mildew as a fungicide. Although it isn’t very effective against hard-bodied pests, it can kill their eggs and the larvae, which stop them from multiplying.
Pyrethrum spray is a natural pesticide. Pyrethrin is an active ingredient in the pyrethrum spray derived from chrysanthemums by using the oils found within plants.
As it comes from plants, then it is a safe way to repel pests without causing any harm to humans as well as pets in the house.
The Pyrethrum spray is highly capable of repelling the most harmful pests like Aphids, flies, and different types of mites.
Pyrethrum spray is readily available in online stores. But in case you still can’t find one, go for pyrethrin pesticide as a substitute.
To use it, mix 2-3 tsp of it into the one gallon of water and fill it into a spray bottle, and you are ready to go.
Don’t forget to read the warnings and precautions mentioned on the packet before using it.
One of the easiest methods to get rid of pests is soapy water.
The commercial insecticidal soap is the safest choice for ZZ plants because these soaps are in existence precisely to control the pests without injuring the plant.
Hand soap and liquid hand wash are less expensive and somehow effective too.
Garlic is a natural and super-effective insect repellent. Here is a straightforward method to prepare an organic pesticide that you can prepare at home.
- Take a garlic bulb and crush, or even better, grind it to make a thick paste.
- Now, put the paste into a jar with 250ml of water.
- Close the jar tightly and keep it closed for 24 hours
- Now, after 24 hours, shake the jar well and apply it all over the ZZ plant. You can also use a spray bottle for spraying. Just make sure to spray each portion of the plant.
Apart from these, there are several other ways to get rid of pests in your ZZ plant. You can read more about it in our article called how to eliminate bugs on the ZZ plant.
Now, talking about the fertilizing needs of the ZZ plants, it’s sometimes forgiving, and it will do quite good in the short run. However, it can be a bad idea not to fertilize your ZZ plant in the long run.
As the plant is potted in a small pot, the soil will lose its nutrients over time, and hence it’s vital to fertilize the plant at least once in a while.
For the optimum growth of the ZZ, fertilize the plant at least once every two months during the spring and summer seasons, whereas it doesn’t need any fertilization during fall and winter.
But as I already mentioned, ZZ plants are slow growers, so always use a mild fertilizer dose as over-fertilizing can raise many issues.
Espoma Organic Indoor Liquid Organic Plant Food is an excellent organic solution for beginners.